Below you'll find a link to download a PDF of the first chapter of GMAT Math Deconstructed. Ultimately, I'm hoping to post a complete guide to all of the different math topics on the GMAT, creating a map, or toolbox of all of the different skills and information you'll need, to do well on the test...
Chapter 1 (PDF download) covers some introductory basics, and most of the material you will need to know about integers, which is a particular fascination of GMAT question writers. Chapter 2 will cover fractions, decimals and percents. There will probably be somewhere between 10 to 12 chapters, when all is said and done...
An ultimate guide to solving the math section of the GMAT